This invention relates generally to manufacturing components, and more specifically to methods and interchangeable apparatus for accurately and controllably locating tools on workpieces during manufacturing operations such as polishing, deburring, materials removal and other machining and inspection operations.
Complexly shaped articles, such as blisks used in aircraft engines, are manufactured by techniques using specially shaped tooling that accomplish material removal from the work piece. In an example of particular interest, an integral compressor blade/disk (BLISK) structure of a gas turbine engine is manufactured as a single piece by machining methods such as milling and electro chemical machining (ECM). Finish machining operations such as polishing and deburring of machined components such as BLISKs are needed and have to be performed so as to avoid damaging these expensive components. Due to the complex geometries involved in BLISKs, many of the finishing operations are done manually.
Multi-axis robots which reproduce the motions of humans have sometimes been used for finish machining operations such as polishing and deburring. For example, for deburring of complex shaped articles such as BLISKs, conventional multi-axis robots using an air powered abrasive belt tool at the end of a robot arm have been used. However, these conventional robot arms use the same tool previously controlled by humans and reproduce the motions of a human performing this task. This approach has severely limited the use of robots for finishing operations on complex geometries such as BLISKs because the abrasive belt polishing tool must be kept away from critical geometric features that are not easily accessible. To avoid costly damage to these expensive components, the conventional abrasive belt tool must be kept away from critical geometry due to its constantly changing overall length and true position due to inherent belt stretching and belt tracking. This is especially a problem in robotic or automatic machining systems which lack the hand-eye coordination of humans. The constantly changing true position and tool conditions such as stretching and tracking of the machining tool have severely limited the use of robotic polishing and deburring of critical components such as BLISKs. Manufacturing individual components of a fixture for use in machining or inspection operations inherently involves some variations due to manufacturing tolerances and assembly stack-ups. These manufacturing tolerances and assembly stack-ups conventionally have resulted in variations in the location of the machining or inspection tool center point. In manufacturing operations a large number of tool assemblies and robots are used and conventional methods of accounting for the manufacturing variations in tools are not adequate to ensure precise location and control of tool center point within complex geometry parts such as BLISKs.
Accordingly, it would be desirable to have a system for performing automated finish machining operations on complex geometries such as BLISKs without causing damage to the component. It would be desirable to have a device that maintains the true position in space of the contact point of the machining tool regardless of changes in tool conditions such as belt wear, stretching, tracking, tension changes and other causes. It is desirable to have a method of making a device for use in manufacturing and inspection operations on complex geometries that can maintain the true position in space of a tool that can be controlled automatically in robots or other automated systems. It is desirable to have a method of manufacturing a tool assembly such that various tools can be interchanged while maintaining the precision of location of the tool center point.